John H. Hemann

John is a Chambers-ranked trial lawyer who handles complex, high-stakes business litigation, government investigations and white collar criminal cases, particularly for technology clients. A former Assistant US Attorney (AUSA), John has tried nearly 40 cases, including groundbreaking jury trials under the Computer Fraud and Abuse Act (CFAA) and the Economic Espionage Act.

Throughout his career, John has represented clients in their most critical legal matters. His complex civil litigation experience spans unfair competition, trade secrets, business torts, contract disputes and computer fraud and abuse. John and his Cooley team successfully tried the first civil CFAA case to reach a jury on behalf of an international ecommerce company. He represents a major bank in trade secret and business tort litigation stemming from the collapse of Silicon Valley Bank, as well as a leading ecommerce platform in unfair competition litigation against its primary competitor.

In addition to his complex civil practice, John has an active white collar and investigations practice, for which he is ranked by Chambers. He has represented major corporations and financial institutions in federal and state investigations involving fraud, trade secret theft and antitrust. John also advises high-profile executives in criminal and US Securities and Exchange Commission matters, including investor fraud, insider trading, bribery, national security, antitrust and trade secret theft. He conducts sensitive internal investigations into financial fraud and executive misconduct, often persuading authorities to dismiss cases, reduce charges or vacate prior convictions.

Before joining Cooley, John served as deputy chief of the Criminal Division with the US Attorney’s Office for the Northern District of California and chief of its Special Prosecutions section. Over the course of his career as a prosecutor, he handled and supervised the full range of federal criminal cases, including securities and other major frauds, cybercrime, national security and public corruption. As an AUSA, John successfully tried corporate fraud cases, police misconduct cases and many others, including the first economic espionage case to be tried to a jury. John was also a member of the high-profile Enron task force, where he prosecuted Enron’s chief financial officer, successfully tried a six-defendant case and was co-lead prosecutor on the indictment of Enron Chairman Ken Lay. 

John is a member of the Board of Trustees of The College of Wooster.